Anandtech published AMD Reveals the X570 Chipset: PCIe 4.0 is Here
A quote from the article:
At Computex 2019 during AMDs keynote, AMD CEO Dr. Lisa Su unveiled details new X570 chipset designed for the upcoming Ryzen 3000 series "Matisse" processors. The new 3rd generation of AM4 motherboards include PCIe 4.0 support, native USB 3.1 Gen2 ports, and a slightly more power hungry TDP, which means motherboard manufacturers are required to use actively cooled chipset heatsinks.AMD Reveals the X570 Chipset: PCIe 4.0 is Here
The new X570 chipset marks the first consumer motherboard chipset to feature PCIe 4.0 by default. We saw that manufacturers were preparing its previous generation X470/B450 motherboards to offer limited PCIe 4.0 support through a wave of firmware updates – taking advantage of the CPUs independent on-die PCIe controller – but due to certain requirements of PCIe 4.0, its likely that previous generation boards will only have the top full-length slot running PCIe 4.0 when paired with a Ryzen 3000 series processor. The limitations are due to the length of the traces that the PCIe 4.0 interface requires. This means traces longer than a few inches wont be able to operate PCIe 4.0 unless the traces are fitted with redrivers to push the signal further down the board.